Copper-steel brazing connection structure and refrigeration fitting

Abstract

The application provides a copper-steel brazing connection structure and a refrigeration accessory. The copper-steel brazing connection structure comprises a stainless steel pipe and a copper sleeve. The stainless steel pipe comprises a body section and a connecting section. The copper sleeve comprises a first connecting section, a transition section and a second connecting section. The first connecting section and the transition section are sleeved and welded to the connecting section of the stainless steel pipe, and the transition section and the second connecting section are sleeved and welded to an external copper pipeline. The stainless steel pipe, the copper sleeve and the external copper pipeline overlap at the transition section, the axial length of the transition section is L0, the axial length of the first connecting section is L1 and L1 is greater than or equal to 0, and the total axial length of the transition section and the second connecting section is L. L0 is greater than or equal to 0.3L, and L0+L1 is greater than or equal to a length critical value predicted by a length prediction model. L0+L1 is accurately controlled by the length prediction model, and L0+L1 with economic benefits is selected under the premise that the brazing layer after welding of the equipment end can still meet the welding performance requirements, so as to realize balanced control of the welding performance and the copper material cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of refrigeration, and particularly relates to a copper-steel brazing connection structure and a refrigeration accessory. BACKGROUND

[0002] Based on the excellent ductility and thermal conductivity of copper material, a large number of copper material products are applied in the existing refrigeration system. In order to solve the cost problem caused by high copper price, the stainless steel replacement of copper material and the installation and connection requirements after the stainless steel replacement gradually become the focus of research and development in the industry.

[0003] For stainless steel accessories or pipes, flame brazing is usually used when they are welded with copper pipes in the equipment end pipeline. Based on the easy oxidation of stainless steel, oxidation is easily generated during flame brazing, even if the flux is added, the oxidation cannot be completely avoided, and then the welding problems such as virtual welding or broken welding of the weld are caused. In order to make the stainless steel product meet the welding quality requirements of the equipment end, a red copper transition piece is usually welded by furnace brazing at the assembly end of the stainless steel product. When the equipment end is welded, the red copper transition piece on the stainless steel product and the copper pipe in the pipeline are flame brazed, thereby effectively solving the problem that the stainless steel product is difficult to be flame brazed with the external copper pipeline of the customer end.

[0004] Although the setting of the red copper transition piece solves the problem of the feasibility of the welding of the stainless steel product at the equipment end, the welding structure brings new welding problems. Specifically, since the red copper transition piece and the stainless steel product belong to dissimilar metal welding, the solder selected during furnace brazing needs to consider the melting points of both, so the tin bronze solder with a relatively low melting point is usually selected. When the red copper transition piece is welded and connected with the copper pipeline at the equipment end, the heat of welding causes the tin bronze weld to appear secondary welding fusion, thereby causing the problems of solder loss, insufficient welding depth and poor welding strength. In addition, since the red copper transition piece and the stainless steel product are brazed in the furnace, long-time furnace brazing causes the grain size of the red copper transition piece to be coarse and reduces the tensile strength thereof. Therefore, the existing stainless steel product using the red copper transition piece for transition welding not only has a relatively long length of the red copper transition piece to avoid the secondary welding fusion caused by the welding at the equipment end, but also has a very thick wall thickness of the red copper transition piece to compensate for the reduction of the tensile strength caused by the increase of the grain size after the furnace brazing. However, the increase of the length and the wall thickness causes the dramatic increase of the material consumption of the red copper transition piece, thereby greatly increasing the material cost. SUMMARY

[0005] The present application is provided in order to overcome the deficiencies of the prior art, and provides a copper-steel brazing connection structure and a refrigeration accessory.

[0006] In order to achieve the above object, the application discloses a copper-steel brazing connection structure, which comprises a stainless steel pipe and a copper sleeve. The stainless steel pipe comprises a body section and a connecting section. The copper sleeve comprises a first connecting section, a transition section and a second connecting section, the first connecting section and the transition section are sleeved and welded to the connecting section of the stainless steel pipe, the transition section and the second connecting section are sleeved and welded to an external copper pipeline, the stainless steel pipe, the copper sleeve and the external copper pipeline overlap at the transition section, the axial length of the transition section is L0, the axial length of the first connecting section is L1 and L1≥0, and the total axial length of the transition section and the second connecting section is L; L0≥0.3L and L0+L1 satisfy the following length prediction model:

[0007]

[0008] wherein, is the specific heat capacity of the copper material; is the density of the copper material; is the thermal conductivity of the copper material; is the outer diameter of the transition section of the copper sleeve; T is the wall thickness of the transition section of the copper sleeve; the coefficient A satisfies 0.11≤A≤1.02.

[0009] According to an embodiment of the application, the coefficient A monotonically increases with the outer diameter of the transition section of the copper sleeve and monotonically decreases with the wall thickness T of the transition section of the copper sleeve.

[0010] According to an embodiment of the application, the coefficient A satisfies the following functional relationship with the outer diameter of the transition section of the copper sleeve and the wall thickness T of the transition section of the copper sleeve:

[0011]

[0012] wherein, 19≤k≤21.5 and 0.94≤ ≤0.98.

[0013] According to an embodiment of the application, the connecting section of the stainless steel pipe, the first connecting section of the copper sleeve and the transition section of the copper sleeve are all straight pipe sections; the joint between the connecting section and the body section of the stainless steel pipe has a protrusion directed to the center of the stainless steel pipe to define a stainless steel positioning ring or a stainless steel positioning protrusion on the end face of the first connecting section of the copper sleeve; the joint between the transition section and the first connecting section of the copper sleeve has a protrusion directed to the center of the copper sleeve to define a copper sleeve positioning ring or a copper sleeve positioning protrusion on the end face of the external pipeline.

[0014] According to an embodiment of the application, the connecting section of the stainless steel pipe is in a flared structure, the first connecting section and the transition section of the copper sleeve are both straight pipe sections, and the flared reducing section on the connecting section of the stainless steel pipe defines the end face of the first connecting section of the copper sleeve.

[0015] According to an embodiment of the present application, the connecting section of the stainless steel pipe is in a flared structure, and the first connecting section of the copper sleeve is connected to the connecting section of the stainless steel pipe after being shrunk.

[0016] In another aspect, the present application also provides a refrigeration fitting, which is any one of a distributor, a receiver, a compressor, a muffler, a gas-liquid separator, a drying filter and a fluid distributor / collector, and the input pipe and / or the output pipe of the refrigeration fitting comprises any one of the copper-to-steel brazing connection structures.

[0017] According to an embodiment of the present application, the refrigeration fitting is a distributor and comprises a stainless steel body and a stainless steel end cover, and the output pipe of the distributor is a plurality of branch pipes;

[0018] When the input pipe of the distributor comprises the copper-to-steel brazing connection structure, the stainless steel pipe body section is directly connected to the input pipe hole on the stainless steel end cover or is connected to the input pipe hole on the stainless steel end cover through a stainless steel throttle pipe, and the transition section and the second connecting section of the copper sleeve are connected to the external copper pipeline on the side of the distributor input pipe;

[0019] When the branch pipe of the distributor comprises the copper-to-steel brazing connection structure, the stainless steel pipe body section is connected to the shunt branch pipe hole on the stainless steel body, and the transition section and the second connecting section of the copper sleeve are connected to the external copper pipeline on the side of the distributor branch pipe.

[0020] According to an embodiment of the present application, the refrigeration fitting comprises a stainless steel body and a stainless steel end cover which are cover-welded to each other, the stainless steel end cover has an assembly hole, and the assembly hole on the stainless steel end cover is connected to the stainless steel pipe body section in the copper-to-steel brazing connection structure.

[0021] According to an embodiment of the present application, the refrigeration fitting comprises a stainless steel body and a stainless steel end cover which are integrally formed, the stainless steel end cover has an assembly hole, and the stainless steel pipe body section in the copper-to-steel brazing connection structure is welded to the assembly hole;

[0022] Alternatively, the refrigeration fitting comprises a stainless steel body and a stainless steel end cover, the stainless steel pipe in the copper-to-steel brazing connection structure is connected to the stainless steel end cover, and the stainless steel body, the stainless steel end cover and the stainless steel pipe are integrally formed.

[0023] According to an embodiment of the present application, the refrigeration fitting is a fluid distributor / collector, the fluid distributor / collector comprises a collecting pipe, a main pipe and a plurality of branch pipes, the main pipe has a collecting pipe hole and a plurality of branch pipe holes on the pipe wall, and the collecting pipe and / or the branch pipe adopts the copper-to-steel brazing connection structure;

[0024] When the collecting pipe adopts the copper-to-steel brazing connection structure, the collecting pipe hole on the main pipe is connected to the stainless steel pipe body section in the copper-to-steel brazing connection structure;

[0025] When the branch pipe adopts the copper-steel brazing connection structure, the branch pipe hole on the main pipe is connected to the stainless steel pipe body section in the copper-steel brazing connection structure.

[0026] In summary, the copper-steel brazing connection structure provided by the application inserts the transition section of the external copper pipeline into the copper sleeve pipe to make the stainless steel pipe, the copper sleeve pipe and the external copper pipeline overlap at the transition section. By controlling the ratio of the axial length L0 of the transition section to the total axial length L of the transition section and the second connection section, the problem of the decrease in pressure resistance caused by the increase in grain size of the copper sleeve pipe after brazing in the furnace is compensated, and the product after welding can meet the design requirements in terms of burst pressure and fatigue life. At the same time, based on the given outer diameter D and wall thickness T of the transition section of the copper sleeve pipe, the length L0+L1 of the copper sleeve pipe inserted into the stainless steel pipe is accurately controlled through the length prediction model, and the optimal economic benefit of the insertion depth of the copper sleeve pipe is selected to realize the balanced control of the welding performance and the cost of copper material on the premise that the brazing layer between the copper sleeve pipe and the stainless steel pipe after welding of the equipment end is still not affected by the secondary welding to ensure the welding sealing and the welding strength.

[0027] To make the above and other objects, features and advantages of the present application more obvious and easy to understand, the following preferred embodiments are specifically described below with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 Fig. 1 shows a schematic diagram of a copper-steel brazing connection structure provided by an embodiment of the application.

[0029] Figure 2 Fig. 2 shows a schematic diagram of the copper-steel brazing connection structure after the external copper pipeline is connected. Figure 1 Fig. 3 shows a schematic diagram of the structure of the copper-steel brazing connection structure after the external copper pipeline is connected.

[0030] Figure 3 Fig. 4 shows a schematic diagram of a copper-steel brazing connection structure provided by another embodiment of the application.

[0031] Figure 4 Fig. 5 shows a schematic diagram of a copper-steel brazing connection structure provided by another embodiment of the application.

[0032] Figure 5 Fig. 6 shows a schematic diagram of the structure of the copper-steel brazing connection structure after the external copper pipeline is connected. Figure 4 Fig. 7 shows a schematic diagram of the structure of the copper-steel brazing connection structure after the external copper pipeline is connected.

[0033] Figure 6 Fig. 8 shows a schematic diagram of a distributor structure using a copper-steel brazing connection structure.

[0034] Figure 7 Fig. 9 shows a schematic diagram of the structure of the distributor after the copper-steel brazing connection structure is removed. Figure 6 Fig. 10 shows a schematic diagram of the structure of the distributor after the copper-steel brazing connection structure is removed.

[0035] ​Figure 8 Fig. 1 shows a schematic diagram of a distributor structure with a copper-steel brazing connection structure for an output pipe (branch pipe).

[0036] Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Fig. 5 shows a schematic diagram of a structure in which the copper-steel brazing connection structure is applied to an input pipe or an output pipe of a refrigeration fitting in other embodiments.

[0037] Figure 14 Fig. 6 shows a schematic diagram of a structure in which the copper-steel brazing connection structure is applied to a fluid distributor / collector in other embodiments.

[0038] Figure 15 Fig. 7 shows an enlarged schematic diagram of position A in Fig. 6. Figure 14 DETAILED DESCRIPTION

[0039] To solve the welding problems of low tensile strength caused by coarse grain size after brazing in the furnace and secondary welding of the brazing layer caused by welding at the equipment end on the red copper transition piece of a stainless steel product, the current main solution is to increase the wall thickness and length of the red copper transition piece. As described above, the double increase of the wall thickness and length will greatly increase the amount of copper material, which will bring great pressure to the cost of the entire product. In addition, based on the limitation of the cross-sectional area of the refrigerant flow in the refrigeration system and the assembly size when connecting the external copper pipe at the equipment end, the wall thickness of the red copper transition piece can only be adjusted within a very limited range; that is, the way to increase the wall thickness to compensate for the reduction of tensile strength caused by coarse grain size is very limited; and within the limited wall thickness range, the longer the length of the red copper transition piece, the greater the risk of explosion leakage.

[0040] Therefore, the present embodiment provides a copper-steel brazing connection structure 10, which comprises a stainless steel pipe 1 and a copper sleeve 2. The stainless steel pipe 1 comprises a body section 11 and a connecting section 12. The copper sleeve 2 comprises a first connecting section 21, a transition section 22, and a second connecting section 23, the first connecting section 21 and the transition section 22 are sleeved and welded to the connecting section 12 of the stainless steel pipe 1, and the transition section 22 and the second connecting section 23 are sleeved and welded to the external copper pipe 20. The stainless steel pipe 1, the copper sleeve 2, and the external copper pipe 20 overlap at the transition section 22, and the axial length of the transition section 22 is L0, the axial length of the first connecting section 21 is L1 and L1≥0, and the total axial length of the transition section 22 and the second connecting section 23 is L; L0≥0.3L and L0+L1 satisfy the following length prediction model:

[0041]

[0042] wherein, is the specific heat capacity of the copper material;​​​​​ The density of copper material; The thermal conductivity of copper. Let T be the outer diameter of the copper sleeve transition section; T be the wall thickness of the copper sleeve transition section; and the coefficient A must satisfy: 0.11≤A≤1.02.

[0043] In the copper-steel brazed connection structure provided in this embodiment, although the copper sleeve 2 and the stainless steel pipe 1 still exhibit coarse-grained microstructure after furnace brazing, resulting in reduced pressure resistance during pipe connection, when connected to external copper pipelines at the equipment end, such as... Figure 2 As shown, the external copper pipe 20 is fitted inside the second connecting section 23 and transition section 22 of the copper sleeve. That is, the external copper pipe 20, the copper sleeve 2, and the stainless steel pipe 1 are sequentially fitted together and overlap at the transition section 22 on the copper sleeve 2. This structure ensures that the copper sleeve 2 no longer bears pressure alone at any point in the axial direction, but shares the pressure with the connecting section 12 of the stainless steel pipe and / or the external copper pipe 20. Specifically, at the first connecting section 21, the copper sleeve 2 shares the pressure with the stainless steel pipe connecting section 12 covering it; at the transition section 22, the external copper pipe 20, the copper sleeve transition section 22, and the stainless steel pipe connecting section 12 share the pressure; and at the second connecting section 23, the copper sleeve 2 bears the pressure together with the external copper pipe 20 fitted inside it. The overlapping reinforcement of the external copper conduit 20 and / or stainless steel conduit 1 can effectively solve the problem of low pressure resistance caused by the coarse grain size of the copper sleeve 2 after brazing in the furnace. Compared with the existing copper transition pipe, the wall thickness of the copper sleeve 2 can be designed to be thinner to reduce material consumption. On this basis, by controlling the ratio between the length L0 of the transition section 22 and the total axial length L of the transition section 22 and the second connecting section 23 (L0≥0.3L), the length of the overlapping area is ensured, thereby further improving the welding strength of the three components and the pressure resistance at the location of the copper sleeve 2 so that both welding performance and service life can meet the design requirements.

[0044] Regarding the secondary welding fusion issue caused by welding external copper pipes at the equipment end, those skilled in the art can currently only adjust the length of the copper transition piece based on experience or feedback from the equipment end to minimize the impact of secondary welding fusion on the brazing layer. However, this length adjustment based on experience is very vague and lacks versatility, which poses significant challenges to product design and promotion. To solve this problem, based on... Figure 1 The inventors conducted extensive testing on the pipe fittings formed by the copper-steel brazed connection structure provided in this embodiment; the test conditions were derived from the pressure test of standard GB 4706.32-2012 / IEC60335-2-40:2005. Although this embodiment uses... Figure 1The stainless steel pipe connecting section 12, the first connecting section 21 on the copper sleeve, and the transition section 22 are all straight pipe sections, as illustrated in this example. However, the present invention does not limit this in any way. In other embodiments, the stainless steel pipe connecting section 12 may also be a flared structure, and the copper sleeve 2 may be a matching constricted structure (e.g., Figure 4 and Figure 5 ) or the first connecting section and transition section on the copper sleeve are both straight pipe sections (such as Figure 3 (As shown). The expansion and contraction structure limits the insertion depth of the inner sleeve fitting, and its function is similar to... Figure 1 The stainless steel positioning rings on the stainless steel connecting section 12 are identical. Since lengths L, L1, and L0 all refer to axial lengths, the structures on the stainless steel pipe connecting section 12 and the first connecting section 21 of the copper sleeve do not affect the pressure resistance test and burst pressure test of this embodiment.

[0045] The specific test conditions are as follows: The test sample is welded to the equipment end. After welding, the marked area is subjected to pressure resistance test and burst pressure test under the same equipment operating conditions. The pressure required for the pressure resistance test is 4.16 MPa and held for 1 minute. The pressure required for the burst pressure test is 16.4 MPa. After the two tests are completed, the quality of the weld at the marked area is checked.

[0046] Test sample selection: based on the outer diameter of the copper sleeve transition section 22 Nine test groups were selected, and within each test group, four sub-test groups were selected based on the wall thickness T of the copper sleeve transition section 22. Within each sub-test group, five test samples were formed based on the length L0+L1 of the copper sleeve 2 fitted onto the stainless steel pipe connection section 12. Each test sample underwent the above two pressure tests, followed by weld inspection. Specific test data are shown in Appendix Table 1.

[0047] Among them, the outer diameter of the first test group =6mm; its sub-test groups contain wall thicknesses T = 0.35mm, 0.5mm, 0.8mm, 1.1mm; each sub-test group is further divided into five test samples according to the length L0+L1 of the copper sleeve inside the stainless steel pipe connection section.

[0048] Outer diameter in the second test group =9.52mm; its sub-test groups contain wall thicknesses T =0.35mm, 0.55mm, 0.8mm, 1.1mm; each sub-test group is further divided into five test samples according to the length L0+L1 of the copper sleeve inside the stainless steel pipe connection section.

[0049] Outer diameter in the third test group = 12.7 mm; it contains the sub-test groups of wall thickness T = 0.5 mm, 0.7 mm, 0.9 mm, 1.2 mm; each sub-test group is divided into five test samples according to the length L0+L1 of the copper sleeve fitted in the stainless steel pipe connecting section.

[0050] Outer diameter in the fourth test group = 15.9 mm; it contains the sub-test groups of wall thickness T = 0.65 mm, 0.9 mm, 1.2 mm, 1.35 mm; each sub-test group is divided into five test samples according to the length L0+L1 of the copper sleeve fitted in the stainless steel pipe connecting section.

[0051] Outer diameter in the fifth test group = 25 mm; it contains the sub-test groups of wall thickness T = 0.7 mm, 0.9 mm, 1.2 mm, 1.4 mm; each sub-test group is divided into five test samples according to the length L0+L1 of the copper sleeve fitted in the stainless steel pipe connecting section.

[0052] Outer diameter in the sixth test group = 32 mm; it contains the sub-test groups of wall thickness T = 0.9 mm, 1.2 mm, 1.4 mm, 1.6 mm; each sub-test group is divided into five test samples according to the length L0+L1 of the copper sleeve fitted in the stainless steel pipe connecting section.

[0053] Outer diameter in the seventh test group = 45 mm; it contains the sub-test groups of wall thickness T = 1.2 mm, 1.4 mm, 1.6 mm, 1.9 mm; each sub-test group is divided into five test samples according to the length L0+L1 of the copper sleeve fitted in the stainless steel pipe connecting section.

[0054] Outer diameter in the eighth test group = 50 mm; it contains the sub-test groups of wall thickness T = 1.3 mm, 1.6 mm, 1.8 mm, 2.0 mm; each sub-test group is divided into five test samples according to the length L0+L1 of the copper sleeve fitted in the stainless steel pipe connecting section.

[0055] Outer diameter in the ninth test group = 70 mm; it contains the sub-test groups of wall thickness T = 1.5 mm, 1.8 mm, 2.0 mm, 2.2 mm; each sub-test group is divided into five test samples according to the length L0+L1 of the copper sleeve fitted in the stainless steel pipe connecting section.

[0056] Analysis of the above nine sets of test data revealed that the weld quality of the test samples after welding the external copper pipes at the equipment end is directly related to the length L0+L1 of the copper sleeve 2 fitted onto the stainless steel pipe connection section 12. Specifically, in each sub-test group, when the length L0+L1 exceeds a certain critical length value (L0+L1), min The pressure resistance and burst pressure of the subsequently tested samples both met the design requirements. In other words, if the critical length value (L0+L1) can be determined... min Therefore, in product design, it is only necessary to ensure that the length L0+L1 of the copper sleeve 2 inside the stainless steel pipe connection section 12 exceeds this critical length value (L0+L1). min This ensures that the copper-steel brazed connection structure retains good weldability after welding to the external copper piping at the equipment end. Furthermore, such as... Figure 2 As shown, on the copper sleeve 2, based on L0≥0.3L and the welding depth requirement for the length of the second connecting section 23 when welding the external copper pipeline, the larger the length L0+L1 of the copper sleeve 2 fitted inside the stainless steel pipe connecting section 12, the longer the overall length of the copper sleeve 2 will be, and the greater the amount of copper material required will be. Therefore, based on the critical length value (L0+L1)... min The control of the length L0+L1 can also achieve the optimal selection of the amount of copper material used.

[0057] Therefore, the length threshold (L0+L1) in Table 1 is... min Perform the analysis.

[0058] Select the length critical value (L0+L1) for each sub-experiment group. min The corresponding test samples are summarized in Table 2. Further analysis of the data in Table 2 revealed that in each test group, the critical length values ​​(L0+L1) that meet the pressure resistance test and burst pressure test requirements are... min Besides the specific heat capacity of copper materials Density and thermal conductivity In addition to being related to the outer diameter of the copper sleeve transition section 22 in the test sample, it is also related to the outer diameter of the copper sleeve transition section 22 in the test sample. It is related to the wall thickness T. Based on this analysis, a length prediction model for the test sample L0+L1 was constructed through simulation calculations using the data in Table 2.

[0059]

[0060] The coefficient A satisfies: 0.11≤A≤1.02.

[0061] In this embodiment, coefficient A varies with the outer diameter of the copper sleeve transition section. The coefficient A increases monotonically and decreases monotonically with the wall thickness T of the copper sleeve transition section. Specifically, the coefficient A is related to the outer diameter of the copper sleeve transition section. The wall thickness T of the copper sleeve transition section satisfies the following function relationship:

[0062]

[0063] wherein 19≤k≤21.5 and 0.92≤ ≤0.98. Preferably, k=21.02 is set; for Further analysis shows that it gradually decreases with the increase of the outer diameter of the copper sleeve transition section. Therefore, preferably, for the copper-steel brazing connection structure with the outer diameter of the copper sleeve transition section ≤10 mm, 0.97 can be selected; for the copper-steel brazing connection structure with the outer diameter of the copper sleeve transition section 10 mm< ≤30 mm, 0.96 can be selected; for the copper-steel brazing connection structure with the outer diameter of the copper sleeve transition section 30 mm< ≤50 mm, 0.95 or 0.94 can be selected; and for the copper-steel brazing connection structure with the outer diameter of the copper sleeve transition section >50 mm, 0.93 can be selected. However, the present application does not make any limitation thereon. In the design, based on the given outer diameter and wall thickness T of the copper sleeve transition section, the designer can adjust the value of within 0.92≤

[0064] ≤0.98 and the value of k within 19≤k≤21.5 through limited experiments to achieve the optimal sleeve joint length design. In the product design, based on the given outer diameter and wall thickness T of the copper sleeve transition section, the designer can determine the length critical value (L0+L1) min through the length prediction model to achieve the accurate control of the length L0+L1 so that the stainless steel product still has sufficient welding strength and sealing performance after being welded with the external copper pipeline of the equipment end. Further, the length control of the copper sleeve 2 based on the length critical value (L0+L1) min also achieves the control of the copper material cost, i.e. the bidirectional balance of the product performance and cost. The preliminary design of the sleeve joint length of the copper-steel brazing connection structure before the experiment is carried out based on the given outer diameter

[0065] and wall thickness T of the copper sleeve transition section 22 through the length prediction model, which not only greatly improves the development speed and reduces the market risk but also no longer highly depends on the personal experience of the designer, and the design is simpler and more universal.After the length prediction model is obtained, the length prediction model needs to be verified to determine the reliability of the length prediction model. The outer diameter of the copper sleeve transition section 22 of the 36 test samples in Table 2 located at the length critical value is substituted into the length prediction model , and the wall thickness T is substituted into the length prediction model, to predict the length critical value (L0+L1) min of the copper sleeve 2 in each test sample min and the error between the actual length critical value (L0+L1) min and the predicted length critical value (L0+L1) min , the error = [(L0+L1) min - (L0+L1) min / (L0+L1) min . After the simulation data is summarized, as shown in Table 3, the error between the actual length critical value (L0+L1) min and the predicted length critical value (L0+L1) min of all test samples is within 5%. The error result proves that the length prediction model has sufficient reliability, and can provide accurate guidance for the sleeving depth of the copper sleeve when the external copper pipeline of the stainless steel product and equipment end is welded, and can accurately control the length of the copper sleeve 2 to realize the control of the material usage while ensuring that the brazing layer after the external copper pipeline of the equipment end is welded still meets the pressure resistance and burst pressure requirements.

[0066] The length prediction model determines the critical value of the length L0+L1 of the copper sleeve 2 sleeved on the stainless steel pipe connecting section 12. However, in actual application, based on cost control, the preferred setting length L0+L1 is less than or equal to 3 or 50 mm, that is, (L0+L1) min ≤ L0+L1 ≤ min (3 , 50 mm).

[0067] After determining the length L0+L1 of the copper sleeve 2 sleeved on the stainless steel pipe connecting section 12 according to the length prediction model, as Figure 1 and Figure 2As shown, a stainless steel positioning ring 13 is arranged at the joint between the stainless steel pipe connecting section 12 and the body section 11 to protrude towards the center of the stainless steel pipe 1 to define the end face of the copper sleeve pipe 2. In assembly, the positioning assembly based on the stainless steel positioning ring 13 can ensure that the actual sleeve assembly length of the copper sleeve pipe 2 meets the design requirements, and the stainless steel positioning ring 13 can also effectively prevent the copper sleeve pipe 2 from being inserted too far. Similarly, a copper sleeve pipe positioning ring 24 is arranged at the joint between the copper sleeve pipe transition section 22 and the first connecting section 21 to protrude towards the center of the copper sleeve pipe 2 to define the end face of the external copper pipe 20. The copper sleeve pipe positioning ring 24 provides a basis for the sleeve assembly of the external copper pipe 20 at the equipment end to ensure that the actual assembly length meets the design requirement of L0≥0.3L; at the same time, the limiting based on the copper sleeve pipe positioning ring 24 can also prevent the external copper pipe 20 from being inserted too far. However, the present application does not make any limitation in this regard. In other embodiments, a stainless steel positioning protrusion can also be arranged on the stainless steel pipe for positioning; similarly, a copper sleeve pipe positioning protrusion can also be used on the copper sleeve pipe for positioning.

[0068] Figure 3 As shown, another embodiment of the copper-steel brazing connection structure provided by the present application is different from the embodiment provided by the present application in that the stainless steel pipe connecting section 12' is a flared structure, the first connecting section 21 and the transition section 22 of the copper sleeve pipe are both straight pipe sections, and the flared reducing section 121' of the stainless steel pipe connecting section 12' defines the end face of the first connecting section 21 of the copper sleeve pipe to ensure that the length L0+L1 meets the design requirements based on the length prediction model. The joint between the copper sleeve pipe transition section 22 and the first connecting section 21 is provided with a copper sleeve pipe positioning ring 24 protruding towards the center of the copper sleeve pipe 2 to define the end face of the external pipe 20.

[0069] Figure 4 And Figure 5 As shown, another embodiment of the copper-steel brazing connection structure provided by the present application is different from the embodiment provided by the present application in that the stainless steel pipe connecting section 12' is a flared structure, and the first connecting section 21' of the copper sleeve pipe is a matching flared structure. The limitation of the flared reducing section 121' of the stainless steel pipe connecting section 12' on the first connecting section 21' of the copper sleeve pipe 2 can ensure that the length L0+L1 meets the design requirements based on the length prediction model. Similarly, the limitation of the flared reducing section 211' on the first connecting section 21' of the copper sleeve pipe can ensure that the length L0 of the transition section 22 after actual assembly meets the design requirement of L0≥0.3L.

[0070] On the other hand, the present embodiment also provides a refrigeration fitting. Specifically, the refrigeration fitting is a distributor arranged between a throttling device and an evaporator to uniformly and equally distribute the refrigerant flowing out of the throttling device to each branch of the evaporator. Figure 6 And Figure 7As shown, the distributor 40 includes a stainless steel body 41, a stainless steel end cap 42, an inlet pipe 43, and multiple branch pipes 44. The stainless steel end cap 42 is welded to the stainless steel body 41, and the area inside the stainless steel body 41 located below the stainless steel end cap 42 forms a mixing chamber 410. The bottom of the stainless steel body 41 has multiple branch pipe holes (in... Figure 6 The branch pipe is installed inside the branch pipe hole (therefore it is not labeled), and the end cap 42 has an inlet pipe hole 421.

[0071] In this embodiment, the input pipe 43 of the dispenser adopts the copper-steel brazed connection structure provided in this embodiment. Specifically, the stainless steel pipe body section 11 extends from the input pipe hole 421 on the end cap 42 into the body mixing chamber 410, and the stainless steel pipe body section 11 is welded to the flange portion 422 on the input pipe hole 421. The first connecting section 21 and transition section 22 on the copper sleeve 2 are fitted inside the stainless steel pipe connecting section 12', and the external copper pipe on the input pipe 43 side is fitted inside the second connecting section 23 and transition section 22 on the copper sleeve. In the input pipe 43 of this dispenser, the stainless steel pipe connecting section 12' is... Figure 3 The flared structure shown has a flared reducing section 121' on the stainless steel pipe connecting section 12' that limits the end face of the first connecting section 21 on the copper sleeve so that the length L0+L1 (the total axial length of the first connecting section and the transition section) of the copper sleeve 2 fitted inside the stainless steel pipe connecting section 12 satisfies the length prediction model established in this embodiment. Both the first connecting section 21 and the transition section 22 on the copper sleeve 2 are straight pipe sections. A copper sleeve positioning ring 24 is provided at the junction of the first connecting section 21 and the transition section 22 to limit the inner insertion depth of the external copper pipe, ensuring that the axial length L0 of the copper sleeve transition section 22 satisfies L0≥0.3L, where L is the total axial length of the transition section 22 and the second connecting section 23 on the copper sleeve. However, this invention does not impose any limitations on this. In other embodiments, the stainless steel pipe body section, the first connecting section of the copper sleeve, and the copper sleeve transition section can all be straight pipe sections; or, the stainless steel pipe body section can be a flared structure, while the first connecting section and the transition section on the copper sleeve can be straight pipe sections.

[0072] In the dispenser provided in this embodiment, the copper-steel brazed connection structure directly serves as the dispenser's input pipe 43, and the stainless steel pipe body section 11 has a contraction zone 111 with a reduced flow cross-section to throttle and reduce pressure. However, the present invention does not limit this in any way. In other embodiments, the copper-steel brazed connection structure may also be connected to the input pipe hole on the stainless steel end cap via a stainless steel throttling pipe; in this case, the copper-steel brazed connection structure and the stainless steel throttling pipe together form the dispenser's input pipe.

[0073] like Figure 6 and Figure 7As shown, the liquid distributor provided in this embodiment also includes a mixing guide plate 45 disposed within the main body mixing chamber 410. The mixing guide plate 45 has a guide plate mixing chamber 451 and a throttling guide hole 452. The refrigerant input from the stainless steel tube main body section 11 undergoes primary mixing in the guide plate mixing chamber 451; the refrigerant after primary mixing flows back along the guide plate mixing chamber 451 and is then rapidly input into the main body mixing chamber 410 through the throttling guide hole 452 for secondary mixing. Based on the mixing guide plate 45, the refrigerant, after multiple mixing and high-speed throttling, greatly improves the mixing uniformity of the refrigerant gas and liquid phases. However, the present invention does not limit this in any way. In other embodiments, other refrigerant mixing structures or flow splitting structures may also be provided within the liquid distributor.

[0074] Although this embodiment uses the inlet pipe of a distributor as an example to illustrate the application of the copper-steel brazed connection structure, the present invention does not limit it in any way. In other embodiments, such as Figure 8 As shown, the copper-steel brazed connection structure provided by this invention is also applicable to the branch pipe 44, which serves as the output pipe on the distributor. Specifically, the stainless steel pipe body section 11 is welded to the branch pipe hole at the bottom of the stainless steel body 41 (in... Figure 8 A branch pipe (not labeled) is installed inside the branch pipe hole of the distributor. The external copper pipe on the branch pipe side of the distributor is inserted into the transition section 22 and the second connecting section 23 on the copper sleeve. In the branch pipe 44 of the distributor, the axial length L0 of the transition section 22 of the copper sleeve satisfies L0≥0.3L, where L is the total axial length of the transition section 22 and the second connecting section 23 on the copper sleeve; the length L0+L1 (the total axial length of the first connecting section and the transition section) of the copper sleeve 2 inside the stainless steel pipe connecting section 12 will satisfy the length prediction model established above in this embodiment. Alternatively, in other embodiments, both the input pipe and the branch pipe of the distributor adopt the copper-steel brazed connection structure provided in this embodiment.

[0075] exist Figure 8 In the liquid distributor shown, a flow divider 45' is also provided in the mixing chamber 410 of the main body. The flow divider 45' distributes the refrigerant input into the mixing chamber 410 of the main body evenly into multiple branch pipes 44.

[0076] The copper-steel brazing connection structure provided in this embodiment can be applied to welding between any stainless steel product and external copper piping at the equipment end. The stainless steel pipe within the copper-steel brazing connection structure can be separately connected to the stainless steel product or integrally formed with the stainless steel product. The external copper piping is not limited to copper connecting pipes on the equipment end; it can also be the input or output pipe of copper refrigeration accessories at the equipment end.

[0077] Figure 9 to Figure 12The diagram shown is a structural schematic of a refrigeration component including a copper-steel brazed connection structure provided in other embodiments. The refrigeration component 40' can be any one of a liquid receiver, compressor, silencer, gas-liquid separator, and dryer filter. Figure 9 to Figure 12 In the copper-steel brazed connection structure, the stainless steel pipe is welded to the inlet pipe hole on the refrigeration component; while... Figure 13 In the copper-steel brazed connection structure, the stainless steel tube is integrally formed with the refrigeration component body.

[0078] Specifically, such as Figure 9 As shown, the refrigeration component 40' includes a stainless steel body 41' and a stainless steel end cap 42' welded to the stainless steel body 41', with an assembly hole 421' on the stainless steel end cap 42'. In the copper-steel brazed connection structure, the stainless steel tube body section 11 is inner-welded to the flange portion 422' on the assembly hole 421', and the first connecting section 21 and transition section 22 of the copper sleeve 2 are inner-welded to the stainless steel tube connecting section 12. Figure 9 In this design, both the stainless steel pipe connecting section 12 and the copper sleeve 2 are straight pipe sections. At the junction of the stainless steel pipe connecting section 12 and the main body section 11, there is a stainless steel positioning ring 13 that protrudes towards the center of the stainless steel pipe 1 to define the end face of the first connecting section 21 on the copper sleeve. Similarly, at the junction of the copper sleeve transition section 22 and the first connecting section 21, there is a copper sleeve positioning ring 24 that protrudes towards the center of the copper sleeve 2 to define the end face of the external pipeline. Figure 9 In the refrigeration components shown, the axial length L0 of the copper sleeve transition section 22 satisfies L0≥0.3L, where L is the total axial length of the transition section 22 and the second connecting section 23 on the copper sleeve; the length L0+L1 (the total axial length of the first connecting section and the transition section) of the copper sleeve 2 inside the stainless steel pipe connecting section 12 will satisfy the length prediction model established above in this embodiment.

[0079] Figure 10 and Figure 9 The differences lie in the connection method between the stainless steel pipe 1 and the mounting hole 421' on the refrigeration accessory 40', as well as the structural differences between the stainless steel pipe connecting section 12' and the first connecting section 21' of the copper sleeve. Specifically, for example... Figure 10 As shown, the stainless steel pipe body section 11' connected to the assembly hole 421' has a flared structure. This flared structure extends into the assembly hole 421' on the stainless steel end cap 42' and is welded to the inner wall of the assembly hole 421'. In this embodiment, the stainless steel pipe connecting section 12' has a flared structure; correspondingly, the first connecting section 21' of the copper sleeve also has a constricted structure that matches it. Similarly, in Figure 10The axial length L0 of the transition section 22 of the copper sleeve satisfies L0≥0.3L, L being the total axial length of the transition section 22 and the second connecting section 23 of the copper sleeve; the length L0+L1 (total axial length of the first connecting section and the transition section) of the copper sleeve 2 sleeved in the stainless steel pipe connecting section 12 satisfies the length prediction model established in the embodiment.

[0080] Figure 11 The refrigeration fitting shown in Figure 10 is basically similar, except that: Figure 11 the connection manner of the stainless steel pipe 1 and the assembly hole 421' on the refrigeration fitting 40' is different. Specifically, in Figure 11 the flange portion 422' on the assembly hole 421' is welded in the stainless steel pipe body section 11.

[0081] Figure 12 Another refrigeration fitting 40' with a copper-steel brazing connection structure is shown. The refrigeration fitting includes an integrally formed stainless steel body 41' and a stainless steel end cover 42', and the stainless steel end cover 42' has an assembly hole 421'. The stainless steel pipe body section 11 in the copper-steel brazing connection structure is welded to the assembly hole 421'. The first connecting section 21 and the transition section 22 of the copper sleeve 2 are welded to the stainless steel pipe connecting section 12, and the external copper pipeline is connected to the transition section 22 and the second connecting section 23 of the copper sleeve 2. Similarly, in this structure, the axial length L0 of the transition section 22 of the copper sleeve satisfies L0≥0.3L, L being the total axial length of the transition section 22 and the second connecting section 23 of the copper sleeve; the length L0+L1 (total axial length of the first connecting section and the transition section) of the copper sleeve 2 sleeved in the stainless steel pipe connecting section 12 satisfies the length prediction model established in the embodiment.

[0082] In Figure 12 the stainless steel pipe connecting section 12, the first connecting section 21 of the copper sleeve, and the transition section 22 of the copper sleeve are all straight pipe sections. However, the present application does not make any limitation in this regard. In other embodiments, the stainless steel pipe connecting section can also be a flared structure; and the first connecting section of the copper sleeve can be a matching flared structure. Alternatively, the stainless steel pipe connecting section is a flared structure, while the first connecting section of the copper sleeve and the transition section of the copper sleeve are still straight pipe sections.

[0083] Figure 13 The refrigeration fitting shown in Figure 12 is basically the same, except that: Figure 13In the copper steel brazing connection structure, the stainless steel pipe body 41', the stainless steel end cap 42' and the stainless steel pipe 1 in the copper steel brazing connection structure are integrally formed after spinning. In this structure, the stainless steel pipe body 11 can be understood as the transition section between the stainless steel pipe 1 and the stainless steel end cap 42', and the stainless steel pipe connecting section 12 is sleeved with the copper sleeve pipe 2. As for the connection mode and the length L0 of the copper sleeve pipe 2, L1+L0 are the same as those of the refrigeration fitting shown in Figure 12 The connection mode and the length L0 of the copper sleeve pipe 2 are the same as those of the refrigeration fitting shown in

[0084] Figure 14 As shown in the structure schematic diagram of the copper steel brazing connection structure applied to the fluid distributor / collector, when the fluid is input through the collecting pipe 401 and distributed through the main pipe 402 to the multiple branch pipes 403, the multiple branch pipes 403 are the output pipes of the fluid distributor / collector. When the fluid is input through the multiple branch pipes 403 and collected through the main pipe 402 to the collecting pipe 401, the multiple branch pipes 403 are the input pipes of the fluid distributor / collector.

[0085] As shown in Figure 14 and Figure 15 The fluid distributor / collector 40' includes the collecting pipe 401, the main pipe 402 and the multiple branch pipes 403, the main pipe 402 has multiple branch pipe holes 4021 and collecting pipe holes 4022 on the pipe wall; wherein the collecting pipe 401 and the branch pipe 403 adopt the copper steel brazing connection structure. As for the collecting pipe 401, the collecting pipe holes 4022 on the main pipe 402 are connected to the stainless steel pipe body section 11 in the copper steel brazing connection structure, the first connecting section 21' and the transition section 22 on the copper sleeve pipe 2 are connected to the stainless steel pipe connecting section 12', and the external copper pipe line on the fluid distributor / collector collecting pipe 401 side is inserted into the second connecting section 23 and the transition section 22 on the copper sleeve pipe. As for the branch pipe 403, the branch pipe holes 4021 on the main pipe 402 are connected to the stainless steel pipe body section 11 in the copper steel brazing connection structure, the first connecting section 21 and the transition section 22 on the copper sleeve pipe 2 are connected to the stainless steel pipe connecting section 12', and the external copper pipe line on the fluid distributor / collector branch pipe side is inserted into the second connecting section 23 and the transition section 22 on the copper sleeve pipe.

[0086] In Figure 14 and Figure 15In the embodiment, the collecting pipe 401 and the branch pipe 403 adopt different copper-steel brazing connection structures. Specifically, on the collecting pipe 401, the stainless steel pipe connecting section 12' is in a flared structure; correspondingly, the first connecting section 21' on the copper sleeve pipe is in a matched constricted structure. On the branch pipe 403, the stainless steel pipe connecting section 12' is also in a flared structure, but the first connecting section 21 and the transition section 22 of the copper sleeve pipe are both straight pipe sections and the joint between the two has a copper sleeve pipe positioning ring 24 protruding towards the center of the copper sleeve pipe 2 for limiting the insertion depth of the external copper pipe. However, the present application does not make any limitation in this regard. In other embodiments, the collecting pipe and the branch pipe can also adopt a copper-steel brazing connection structure in which the stainless steel pipe connecting section, the first connecting section of the copper sleeve pipe and the transition section of the copper sleeve pipe are all straight pipe sections; the copper-steel brazing connection structures adopted by the two can also be different.

[0087] Although the copper-steel brazing connection structures on the collecting pipe 401 and the branch pipe 403 are slightly different, for the copper sleeve pipe 2, the axial length L0 of the transition section 22 of the copper sleeve pipe in both satisfies L0≥0.3L, L being the total axial length of the transition section 22 and the second connecting section 23 on the copper sleeve pipe; the length L0+L1 (total axial length of the first connecting section and the transition section) of the copper sleeve pipe 2 sleeved in the stainless steel pipe connecting section 12 will also satisfy the length prediction model established in the above embodiment.

[0088] Although the present embodiment takes the collecting pipe and the branch pipe of the fluid distributor / collector as an example for illustration. However, the present application does not make any limitation in this regard. In other embodiments, only the collecting pipe of the fluid distributor / collector can adopt the copper-steel brazing connection structure; or only the branch pipe of the fluid distributor / collector can adopt the copper-steel brazing connection structure.

[0089] In Figure 14 and Figure 15 The fluid distributor / collector shown in the drawings is a gas collecting pipe or a liquid collecting pipe for transmitting refrigerant. However, the present application does not make any limitation in this regard. When the fluid distributor / collector is a water distributor or a water collector for transmitting water, the collecting pipe and / or the branch pipe thereof can also adopt the copper-steel brazing connection structure provided by the present application.

[0090] In summary, in the copper-steel brazing connection structure provided by the present application, the external copper pipe is sleeved in the transition section on the copper sleeve pipe so that the stainless steel pipe, the copper sleeve pipe and the external copper pipe overlap at the transition section. By controlling the ratio of the axial length L0 of the transition section to the total axial length L of the transition section and the second connecting section, the problem of the decrease of the pressure resistance of the copper sleeve pipe due to the increase of the grain size after brazing in the furnace is compensated, and the products after welding can meet the design requirements in terms of the burst pressure and the fatigue life. At the same time, based on the given outer diameter D of the transition section of the copper sleeve pipe, the axial length L0 of the transition section can be determined. And wall thickness T, through length prediction model accurate control copper bush insert stainless steel pipe length L0+L1, in the premise of ensuring the copper bush and stainless steel pipe between the brazing layer still has no secondary welding melting effect after the equipment end welding to ensure the welding sealing and welding strength, select the economic benefit of copper bush insertion depth to realize the balance control of welding performance and copper material cost.

[0091] Although the present application has been disclosed by the preferred embodiment as above, it is not intended to limit the present application, any skilled person, without departing from the spirit and scope of the present application, can make some changes and modifications, therefore the scope of the present application should be subject to the scope of the claims.

[0092] In table one to table three, the outer diameter of copper bush transition section , the wall thickness T of copper bush transition section, the actual length critical value (L0+L1) min , and the predicted length critical value (L0+L1) min of the copper bush transition section are all in mm. In table three, the unit of specific heat capacity C is J / (kg·℃); the unit of density ρ is g / mm 3 ; the unit of thermal conductivity λ is W / (m·℃), and the unit of coefficient A is mm 2 .

[0093] Table one

[0094]

[0095]

[0096] Table two

[0097]

[0098] Table three

[0099]

Claims

1. A copper-steel brazed connection structure, characterized in that, include: Stainless steel pipe, including the body section and the connecting section; The copper sleeve includes a first connecting section, a transition section, and a second connecting section. The first connecting section and the transition section are inner sleeves welded to the connecting section of a stainless steel pipe. The transition section and the second connecting section are outer sleeves welded to an external copper pipeline. The stainless steel pipe, the copper sleeve, and the external copper pipeline overlap at the transition section, and the axial length of the transition section is L0. The axial length of the first connecting section is L1, and L1≥0. The total axial length of the transition section and the second connecting section is L. L0≥0.3L and L0+L1 satisfies the following length prediction model: ； in, The specific heat capacity of copper. The density of copper material; The thermal conductivity of copper. Let T be the outer diameter of the copper sleeve transition section; T be the wall thickness of the copper sleeve transition section; and the coefficient A must satisfy: 0.11≤A≤1.

02.

2. The copper-steel brazed connection structure according to claim 1, characterized in that, Coefficient A varies with the outer diameter of the transition section of the copper sleeve. It increases monotonically and decreases monotonically with the wall thickness T of the copper sleeve transition section.

3. The copper-steel brazed connection structure according to claim 1, characterized in that, Coefficient A and the outer diameter of the transition section of the copper sleeve The wall thickness T of the transition section with the copper sleeve satisfies the following functional relationship: ； Where 19≤k≤21.5 and 0.94≤k ... ≤0.

98.

4. The copper-steel brazed connection structure according to claim 1, characterized in that, The connecting section of the stainless steel pipe, the first connecting section of the copper sleeve, and the transition section of the copper sleeve are all straight pipe sections; the junction of the connecting section and the main body section on the stainless steel pipe has a stainless steel positioning ring or stainless steel positioning protrusion that protrudes towards the center of the stainless steel pipe to define the end face of the first connecting section on the copper sleeve; on the copper sleeve, the junction of the transition section and the first connecting section has a copper sleeve positioning ring or copper sleeve positioning protrusion that protrudes towards the center of the copper sleeve to define the end face of the external pipeline.

5. The copper-steel brazed connection structure according to claim 1, characterized in that, The stainless steel pipe has a flared joint, while the first connecting section and transition section of the copper sleeve are both straight pipe sections. The flared diameter section on the stainless steel pipe connecting section defines the end face of the first connecting section on the copper sleeve.

6. The copper-steel brazed connection structure according to claim 1, characterized in that, The stainless steel pipe connection section has a flared structure, and the first connection section on the copper sleeve is inner-sleeved and connected to the stainless steel pipe connection section after being narrowed.

7. A refrigeration component, characterized in that, The refrigeration component is any one of a liquid distributor, a liquid receiver, a compressor, a silencer, a gas-liquid separator, a dryer filter, and a fluid distributor / manufacturer. The inlet pipe and / or outlet pipe of the refrigeration component includes the copper-steel brazed connection structure as described in any one of claims 1 to 6.

8. The refrigeration component according to claim 7, characterized in that, The refrigeration component is a liquid distributor, which includes a stainless steel body and a stainless steel end cap. The output pipe of the liquid distributor consists of multiple branch pipes. When the input pipe of the dispenser includes a copper-steel brazed connection structure, the stainless steel pipe body section is directly connected to the input pipe hole on the stainless steel end cap or connected to the input pipe hole on the stainless steel end cap through a stainless steel throttling pipe, and the transition section and the second connecting section on the copper sleeve are connected to the external copper pipeline on the side of the dispenser input pipe. When the branch pipe of the distributor is a copper-steel brazed connection structure, the stainless steel pipe body section is connected to the branch pipe hole on the stainless steel body, and the transition section and the second connecting section on the copper sleeve are connected to the external copper pipeline on the branch pipe side of the distributor.

9. The refrigeration component according to claim 7, characterized in that, The refrigeration component includes a stainless steel body and a stainless steel end cap that are welded together. The stainless steel end cap has an assembly hole, which is connected to the stainless steel tube body section in the copper-steel brazed connection structure.

10. The refrigeration accessory according to claim 7, characterized in that, The refrigeration component includes an integrally formed stainless steel body and a stainless steel end cap. The stainless steel end cap has an assembly hole, and the stainless steel tube body section in the copper-steel brazed connection structure is welded to the assembly hole. Alternatively, the refrigeration component includes a stainless steel body and a stainless steel end cap, with a stainless steel tube in the copper-steel brazed connection structure connected to the stainless steel end cap, and the stainless steel body, stainless steel end cap, and stainless steel tube being integrally formed.

11. The refrigeration component according to claim 7, characterized in that, The refrigeration component is a fluid manifold, which includes a manifold, a main pipe, and multiple branch pipes. The main pipe wall has a manifold hole and multiple branch pipe holes. The manifold and / or branch pipes adopt a copper-steel brazing connection structure. When the manifold adopts a copper-steel brazed connection structure, the manifold hole on the main pipe is connected to the stainless steel pipe body section in the copper-steel brazed connection structure. When the branch pipe adopts a copper-steel brazed connection structure, the branch pipe hole on the main pipe is connected to the stainless steel pipe body section in the copper-steel brazed connection structure.

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